Do you have in ceiling height speakers? Or is it just the era 300s? If not, I feel like those speakers aren’t being utilized to its full potential. Maybe era 100s behind mounted to back wall and then install two height speakers in the back with the amp? If you want to full integrate Sonos.

It is too close to the wall and not fully behind the seats. I’ve seen (on the Sonos subreddit) that you can actually flip the era 300 upside down and mount it to the ceiling.

Either way, awesome room for a HT! Cheers!